Normal intraocular pressure in man.

Whereas the values of 120/70 mm Hg are universally recognized as being normal for the parameter of systemic blood pressure, the value for 'normal intraocular pressure' remains very vague. Indeed, values between 7 and 21 mm Hg are often considered normal. However, a careful review of the literature and original data reported here suggest that the intraocular pressure in normal subjects, although dynamic, is a more accurate parameter than is generally expected. The normal value during the day in healthy, young adults is about 12 +/- 2 mm Hg, and it increases by 1 mm Hg per decade after 40 years of age.